Here is the full list of all 40 Indie Game Battle achievements.
Get 50000 total KOs.
Get 10000 total KOs.
Get 5000 total KOs.
Get 1000 total KOs.
Get 500 total KOs.
Win a match as Sol.
Win a match as Cal.
Win a match as Gontaper.
Win a match as Teslakid.
Win a match as Captain Viridian.
Win a match as Goat.
Win a match as Dust.
Win a match as Pico.
Win a match as Red Drop.
Win a match as Zee Tee.
Win a match as NoLegs.
Win a match as Woodle Tree.
Play a match in Turbo Mode.
Get 100 total KOs.
Win a match as Salad Fingers.
Win a match as The Kid.
Win a match as Bingo.
Win a match as Adventure Pals.
Win a match as Poncho.
Win a match as Max & STEVE.
Win a match as Jarvis.
Win a match as Artist.
Win a match as Electroman.
Win a match as Rex.
Win a match as Gip.
Win a match as Wizard.
Win a match as Huey.
Win a match as Chip.
Win a match as Aria.
Get 10 total KOs!
Win a match as Matt.
Win your first Survival match.
Win a match as Blue Blob.
Launch the game for the first time.
Get 99999 total KOs. Wow, you deserve a cookie for this one.